In mobile communication systems, there is a general requirement to allocate system resources as efficiently as possible based on the number of users in the system and their needs. For example in the wide-band code division multiple access (W-CDMA) systems the optimised management of radio resources requires means for predicting how any change in call configurations affects the signal powers in the cell.
Up-link power increase estimation (PIE) is used to estimate how much the total wide-band interference power changes when the cell load changes. The cell load may change for example due to admission control or due to packet scheduling.
Admission control allows a new user into the radio access network (RAN) if the admission does not cause an excessive interference in the system. Before a new user is admitted to the system, an admission control algorithm estimates the increase in the total interference level due to a new user. This is achieved by using an up-link power increase estimation method.
The packet scheduler allocates up-link packet bit rates to data users by also using the up-link power increase estimation method. By using the up-link power increase estimation method, the packet scheduler estimates by how much the requested/allocated bit rates will increase the noise/interference level. Typically this estimation is also done using a power increase estimation method.
The degree of resource usage in the cell is thus measured with the total received power in the up-link and with the total transmission power in the down-link, which both have particular limits that specify their full usage. In order to distribute system capacity to users optimally, the consumption of each user should be predicted as well as possible prior to the actual admission in the use of capacity. The mapping of call configuration to the signal power depends on diverse factors that change in time.
The power increase estimation methods currently used involve a fixed mathematical formula which is an approximation of the true physical behaviour. As a result of this approximation, the fixed formula provides an error margin in its estimation.
These error margins introduce wasted capacity. If the power increase estimation can estimate the noise rise caused more accurately, the less there is wasted capacity.
It is an aim of the present invention to provide an improved technique for determining a power increase estimation.